perspective

What's the meaning of m34 of the structure CATransform3D, I only know it can change the perspective, but what's the meaning when the value is -0.001 and 0.001? You can find the full details here . Note that Apple uses the reversed multiplication order for projection (relative to the given link) so all matrix multiplications are reversed and all matrices are transposed. A short description of the meaning: m34 = 1/z distance to projection plane (the 1/e z term in the reference link) + for the z axis is towards the viewer, resulting in a "looking in the mirror" feel when using - projection center

I wonder about the gluPerspective parameters. In all examples I see fovy is set to around 45-60degrees I've tried to set it to different values and the object just disappears what's the explanation for it? The aspect value should always be the ratio? why would one change it? zNear, zFar - once again the usual values are around 10 and 500+ what does it reflect? gemse The purpose of the 4 parameters is to define a view frustum , like this: where nothing outside of the frustum should be is visible on screen ( To accomplish this, the parameters are used to calculate a 4x4 matrix, which is then

I have two questions. (I marked 1, 2 below) In OpenGl, the clipping is done by sutherland-hodgman. However, I wonder how to work sutherland-hodgman algorithm in homogeneous system (4D) I made a situation. In VCS, there is a line, R= (0, 3, -2, 1), S = (0, 0, 1, 1) (End points of the line) And a frustum is right = 1, left = -1, near = 1, far = 3, top = 4, bottom = -4 Therefore, the projection matrix P is 1 0 0 0 0 1/4 0 0 0 0 -2 -3 0 0 -1 0 If we calculate the line with the P, then the each end points is like that R' = (0, 3/4, 1, 2), S' = (0, 0, -5, -1) I know that perspective division should

I'm playing around with css transforms and the equivalent filters in IE, and want to simulate perspective by transforming a 2d rectangle into a trapezium. Specifically, I want the right hand side of the rectangle to stay the same height, and the left hand side to be say 80% of the height, so that the mid points of both sides are horizontally in line with each other. I'm familiar with matrix algebra, but can't think how to determine what matrix will do that. For projection, I'd use a 4x4 matrix: 1 0 0 0 0 1 0 0 0 0 0 0 0 0 1/d 1 This works on homogeneous coordinates (d is the distance of the

I've been struggling to implement a quad to quad system in my Android application. The aim is to let the user take a picture, add 4 cornerpoints and have that quad extracted from the image as a rectangle. I had a look at this method and this question to use OpenCV for this. The resulting code is this: public static Bitmap warp(Bitmap image, MyPoint p1, MyPoint p2, MyPoint p3, MyPoint p4) { int resultWidth = 500; int resultHeight = 500; Mat inputMat = new Mat(image.getHeight(), image.getHeight(), CvType.CV_8UC4); Utils.bitmapToMat(image, inputMat); Mat outputMat = new Mat(resultWidth,

And I'm not meaning Bits Per Minute, but Business Process Management. At first though BPM was overestimated, because the technology is somehow easy to address, but I've learned the value of BPM suites is in involving the non-technical, the business experts into the software design. I know, the user is always with us during analysis, but the artifacts we use are always very unfamiliar to them. No matter how friendly the UML diagram looks like, or how many Agile iterations we go into, there is always a gap between the final user and the final developer ( usually covered by the user manager and

It is possible to do an isometric perspective with HTML5 <canvas> ? It is with setTransform ? Or does it exist another way? Example: ctxt.setTransform (1, -0.2, 0, 1, 0, 0); Something like the perspective of Farmville. Thanks a lot. You can draw whatever you want on the canvas down to the individual pixel, so any question like "is it possible" will have a "yes" answer. If you mean if a 3d pipeline is already built-in in the canvas the answer is no, canvas context is 2d so commands are 2d. You can set up a matrix that will make your square-drawing commands looking like an isometric view, but